This invention relates to an image forming apparatus such as an electrophotographic recording apparatus, and relates to a print process cartridge and a toner container used in the image forming apparatus.
In an electrophotographic recording apparatus, a uniformly charged surface of a photosensitive body is exposed to the light to form a latent image. Toner adheres to the latent image by electrostatic force to form a visible toner image, and the visible toner image is transferred to a printing paper. The printing paper is fed through a fixing device by which the toner image is fixed to the printing paper.
In a process in which the toner image is transferred to the printing paper, the residual toner that remains on the photosensitive body is removed by a cleaning device, and collected by a waste toner collecting device. Generally, the waste toner collecting device is detachably mounted in the electrophotographic recording apparatus.
FIG. 19 is an exploded perspective view of the main part of a conventional toner container that constitutes the above described waste toner collecting device. The toner container is able to accommodate waste toner and fresh toner as described later.
As shown in FIG. 19, the toner container 101 includes a fresh toner chamber 102, a waste toner chamber 103, and a partition wall 113 separating the fresh toner chamber 102 from the waste toner chamber 103. A fresh toner supply opening 104 is formed on the bottom of the fresh toner chamber 102, through which the fresh toner is supplied to a not-shown developing device. An opening-and-closing device 106 is rotatably provided in the lower part of the fresh toner chamber 102 and is disposed on the fresh toner supply opening 104. The opening-and-closing device 106 has an opening 108 and an operation lever 107. By operating the operation lever 107 to rotate the opening-and-closing device 106, the opening 108 can be aligned with the fresh toner supply opening 104 so that the fresh toner is supplied to the developing device.
A side plate 120 is provided on the side of the toner container 101. The side plate 120 has fixing projections 114, and is fixed to the toner container 101 so that fixing projections 114 engage fixing holes 105 formed on the toner container 101. The side plate 120 has a waste toner collection opening 109 that opens to the interior of the waste toner chamber 103. A guide frame 110 is formed on the inner side (i.e., the waste toner chamber 103 side) of the side plate 120 in such a manner that the guide frame 110 vertically bridges the waste toner collection opening 109.
A lid 111 is guided by the guide frame 110 so that the lid 111 is slidable within a predetermined range in the longitudinal direction of the toner container 101. The lid 111 is urged by a spring 112 toward the waste toner collection opening 109 so that the lid 111 closes the waste toner collection opening 109 from inside of the waste toner chamber 103.
A screw conveyer (described later) is provided in the electrophotographic recording apparatus for conveying the waste toner removed by the cleaning device from the photosensitive body. When the toner container 101 constructed as above is mounted in the electrophotographic recording apparatus, a toner discharging portion of the screw conveyor urges the lid 111 to open the waste toner collection opening 109, and enters into the waste toner chamber 103 through the waste toner collection opening 109.
In this state, the waste toner is discharged from the screw conveyor so that the waste toner falls from the toner discharging portion. The discharged waste toner is accommodated in the waste toner chamber 103. When the waste toner chamber 103 is filled with the waste toner, or when the fresh toner chamber 102 becomes empty, the toner container 101 is detached from electrophotographic recording apparatus.
When the toner container 101 is detached from the electrophotographic recording apparatus, the toner discharging portion of the screw conveyor is pulled out of the waste toner chamber 103 through the waste toner collection opening 109. In accordance with the movement of the toner discharging portion relative to the waste toner collection opening 109 (caused by the movement of the waste toner collection opening 109 of the toner container 101), the lid 111 moves toward the waste toner collection opening 109 and closes the waste toner collection opening 109 from inside the waste toner chamber 103. Because the waste toner collection opening 109 is closed by the lid 111, the leakage of the waste toner out of the toner container 101 is prevented, when the toner container 101 is detached from the electrophotographic recording apparatus, or when the toner container 101 is transported.
In the above described conventional toner container 101 for the electrophotographic recording apparatus, the waste toner chamber 103 is disposed in a lower part of the toner container 101 as shown in FIG. 19, and therefore the fresh toner chamber 102 has a narrow part. Such a narrow part may be clogged with the fresh toner, and causes a problem that the fresh toner in the upper part of the fresh toner chamber 102 may not be supplied to the developing device.
Moreover, in a state where the toner discharging portion of the screw conveyor has entered into the waste toner chamber 103, no cover is provided above the toner discharging portion of the screw conveyor. The guide frame 110 does not sufficiently cover the toner discharging portion from above. Thus, the waste toner above the guide frame 110 may fall on the toner discharging portion of the screw conveyor or on the path of the lid 111. Accordingly, when the toner container 101 is detached from the electrophotographic recording apparatus, the waste toner may leak out of the toner container 101 in accordance with the movement of the toner discharging portion of the screw conveyor. Particularly, the amount of the toner that falls on the toner discharging portion or the like is larger when the toner container 101 is inclined during the detachment process of the toner container 101 than when the toner container 101 is kept horizontal during the detachment process. This is because the toner in a stationary state may lose its balance when the toner container 101 is inclined.
Further, there is a possibility that the waste toner may leak out of the screw container through the toner discharging portion, when the toner container 101 is attached to or detached from a print process cartridge of the electrophotographic apparatus.
Additionally, there is a type of toner container having another screw conveyor in the waste toner chamber 103. In such a toner container, a load is imposed on a rotation shaft of the screw conveyor by the waste toner. As the amount of the waste toner accommodated in the waste toner chamber increases, the load imposed on the screw conveyor increases, with the result that the screw conveyor may not rotate correctly and may have a difficulty in conveying the waste toner.